The following methods of inspecting a connection state (open/short) of a pn junction by using an electron beam and an open/close state of a contact hole related to a pn junction in a semiconductor device manufacturing process are disclosed.
Japanese Patent Application Laid-Open No. 4-151846 discloses that an open/short-circuit defect of a connection part of a pn junction is found from a voltage contrast image.
Japanese Patent Application Laid-Open No. 11-121561 discloses that an open defect or a short-circuit defect of a contact portion of a pn junction is obtained from a voltage contrast image.
Japanese Patent Application Laid-Open No. 2000-208579 discloses that electric connectivity of a contact hole formed over a p-diffusion layer and an n-diffusion layer is obtained from a voltage contrast image.
Semiconductor device manufacturers have been requesting for measurement of electric characteristics of a pn junction at some midpoint in a wafer process of a semiconductor device. However, none of the above-described prior arts have proposed a method of addressing the request.
None of the above-described prior arts also have proposed a method of detecting and controlling process fluctuations in a wafer process comprised of a plurality of processes at an early stage.